The present invention relates to a spinal fixation device and a method for fixation of that device between two or more vertebrae. More particularly, it relates to a fixation device that results in inherent structural strength due to a unique method for placement of and linkage between the pedicle screws.
One of the significant problems associated with the design of a spinal fixation device is the need for to localize the involvement of the spinal column. Such a fixation device design should involve fixation directly at the site of instability rather than two or three vertebrae away from it. The fixation device should rely on bony tissue rather than intact soft tissue to achieve stabilization and maximum patient comfort, and to encourage rehabilitation. A spinal fixation device should be fully internalized, with no pins transfixing the skin or muscle. Further, it is important that the device be easy to implant in an accurate and consistent manner.
U.S. Pat. No. 4,604,995 discloses a surgical implant having a unitary rod with a generally rectangular configuration formed by a pair of spaced apart branches which are mirror image duplications of one another and equally spaced along their entire length.
U.S. Pat. No. 4,078,559 discloses a straightening and supporting device for the spinal column. The device comprises a rod shaped supporting member at least the length of the spinal column area to be treated and exerting a straightening and supporting effect on the vertebrae of the spinal column.
U.S. Pat. No. 4,003,376 discloses an apparatus for straightening the spinal column. The apparatus includes an elongated member securable forwardly of and against the spinal column. A pair of fastening devices extend around the spinal column from the elongated member to a pair of bands located rearwardly of and adjacent the spinal column.